Compressor system

ABSTRACT

A compressor system ( 10 ) includes a motor ( 3 ) including a rotor ( 31 ) configured to rotate about an axis and a stator ( 32 ) disposed on an outer circumference side of the rotor ( 31 ), a compressor ( 2 ) including an impeller ( 22 ) configured to compress a working fluid ( 31 ) by rotating together with the rotor and a housing ( 23 ) covering the impeller ( 22 ) from an outer circumference side, and a heat exchange flow path ( 600 ) through which a fluid flowing inside the stator ( 32 ) or in a gap between the stator ( 32 ) and the rotor ( 31 ) is flowed and heat is exchangeable between the fluid and the housing ( 23 ).

TECHNICAL FIELD

Priority is claimed on Japanese Patent Application No. 2015-032803, filed Feb. 23, 2015, the content of which is incorporated herein by reference.

BACKGROUND ART

A compressor system in which a motor and a compressor are integrated includes a compressor configured to compress a gas such as air or the like and a motor configured to drive the compressor. In the compressor system, a rotation shaft that extends from a casing of the compressor and a rotation shaft of a motor that similarly extends from a casing of the motor are connected. The rotation of the motor is transmitted to the compressor. The rotation shafts of the motor and the compressor are supported by a plurality of bearings and thus reliably rotate.

Such a compressor system is used for, for example, a subsea production system as in Non-Patent Document 1 or a Floating Production Storage and Offloading (FPSO) unit as in Non-Patent Document 2. When the compressor system is used for the subsea production system, the compressor system is installed in the seabed. The compressor system sends production fluids mixed with crude oils and natural gases that are drawn from production wells drilled to a depth of several thousand meters in the seabed to the sea surface. When the compressor system is used for the FPSO unit, the compressor system is installed in a marine facility such as a ship.

CITATION LIST Non-Patent Literature Non-Patent Document 1 Non-Patent Document 2

Turbomachinery International September/October 2014 P18-P24

SUMMARY OF INVENTION Technical Problem

Incidentally, when a compressor of a compressor system is stopped or is operated normally, temperatures of components composing the compressor such as an impeller and a housing are different. In particular, in the impeller and the housing, due to a high volume difference in members, the degrees of changes in temperatures when they are activated or stopped are different. Therefore, since a difference of temperatures between the impeller and the housing becomes larger according to operation conditions of the compressor system, the amount of thermal elongation greatly deviates, and the clearance between the impeller and the housing varies. As a result, there is a possibility of a space between the impeller and the housing being excessively narrowed and the impeller and the housing coming into contact with each other while the compressor system is activated or stopped.

The present invention provides a compressor system in which a space between an impeller and a housing is able to be prevented from being excessively narrowed.

Solution to Problem

In order to address the above problems, the present invention proposes the following solutions.

A compressor system according to a first aspect of the present invention includes a motor including a rotor configured to rotate about an axis and a stator that is disposed on an outer circumference side of the rotor; a compressor including an impeller configured to compress a working fluid by rotating together with the rotor and a housing covering the impeller from an outer circumference side; and a heat exchange flow path through which a fluid flowing inside the stator or in a gap between the stator and the rotor is circulated and heat is exchangeable between the fluid and the housing.

In such a configuration, the temperature of the fluid flowing inside the stator or in a gap between the stator and the rotor is increased by cooling the stator and the rotor. The fluid whose temperature has increased exchanges heat with the housing through the heat exchange flow path, so as to efficiently and quickly heat the housing. As a result, according to a temperature change in the impeller when the compressor system is activated or stopped, it is possible to quickly heat the housing. Therefore, it is possible to reduce the difference between an amount of thermal elongation of the impeller and an amount of thermal elongation of the housing.

In a compressor system according to a second aspect of the present invention, in the first aspect, the fluid may be a working fluid that is compressed by the impeller.

In such a configuration, the rotor and the stator can be cooled by the working fluid whose temperature has increased when it is compressed by the impeller. As a result, the working fluid can be further heated and supplied to the housing. Therefore, it is possible to effectively heat the housing.

In a compressor system according to a third aspect of the present invention, in the first or second aspect, a flow rate adjusting unit configured to adjust a flow rate of the fluid that circulates in the heat exchange flow path when a temperature difference between the housing and the impeller satisfies a requirement of a predetermined reference may be included.

In such a configuration, when the temperature difference between the housing and the impeller satisfies a requirement of a predetermined reference, the flow rate of the fluid is adjusted by the fluid adjusting unit. Therefore, only a necessary amount of the fluid can be circulated in the heat exchange flow path. Therefore, for example, when the temperature difference between the housing and the impeller is small and there is no need to heat the housing, it is possible to prevent the fluid from being continuously circulated in the heat exchange flow path. Therefore, it is possible to efficiently circulate the fluid in the heat exchange flow path.

Advantageous Effects of Invention

According to the compressor system of the present invention, it is possible to heat the housing using the fluid whose temperature has increased when the rotor and the stator are cooled. As a result, it is possible to prevent a space between the impeller and the housing from being excessively narrowed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram showing a compressor system according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a compressor system according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a compressor system according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram showing a compressor system according to a fourth embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS First Embodiment

A first embodiment according to the present invention will be described below with reference to FIG. 1.

A compressor system 10 is provided in the seabed for a subsea production system that is one for ocean oil and gas field development methods and is provided on the sea surface for a Floating Production Storage and Offloading (FPSO) unit. The compressor system 10 pressure-feeds a production fluid such as oils and gases harvested from oil gas field production wells that are located several hundreds to thousands of meters from the seabed as a working fluid.

As shown in FIG. 1, the compressor system 10 includes a compressor 2, a motor 3, a bearing 4, a casing 5, a heat exchange flow path 600, and a flow rate adjusting unit 7. The compressor 2 includes a shaft 21 that extends in an O axis direction (in a horizontal direction in FIG. 1) as a rotation shaft. The motor 3 includes a rotor 31 that is directly connected to the shaft 21.

The bearing 4 supports the shaft 21. The casing 5 accommodates the motor 3 and the compressor 2. In the heat exchange flow path 600, heat exchange with a fluid that circulates therein occurs and thus a housing 23 of the compressor 2 is heated. The flow rate adjusting unit 7 adjusts the flow rate of a fluid that circulates in the heat exchange flow path 600.

The compressor 2 is accommodated inside the casing 5. The compressor 2 compresses a working fluid when the shaft 21 rotates about an O axis together with the rotor 31. The compressor 2 of this embodiment includes the shaft 21, an impeller 22, and the housing 23. The shaft 21 extends in the O axis direction. The impeller 22 is fixed to an outer circumference surface of the shaft 21 and rotates together with the rotor 31 thereby to compress a working fluid. The housing 23 covers the impeller 22 from the outside.

The shaft 21 is a rotation shaft that extends in the O axis direction. The shaft 21 is supported by the casing 5 to be rotatable about the O axis. The shaft 21 passes through the housing 23 in the O axis direction. The shaft 21 has ends both of which extend from the housing 23. The shaft 21 extends in the O axis direction in the casing 5 to be described below.

The impeller 22 rotates together with the shaft 21 and compresses a working fluid that passes through the inside of the impeller 22 to generate a compressed fluid. A plurality of impellers 22 are fixed to the outer circumference surface of the shaft 21 side by side with spaces therebetween in the O axis direction.

The housing 23 is an exterior of the compressor 2. The housing 23 accommodates the impeller 22 therein. The housing 23 is accommodated inside the casing 5. In the housing 23, a plurality of internal spaces 23 a whose diameters are repeatedly reduced and increased are provided. The impeller 22 is accommodated in the internal space 23 a. In the internal space 23 a, the impeller 22 is disposed with a predetermined space between itself and the housing 23. In the housing 23, a flow path (not shown) through which a working fluid is circulated from the impeller 22 disposed on an upstream side (the right side in FIG. 1) that is one side in the O axis direction to the impeller 22 adjacent on a downstream side (the left side in FIG. 1) that is the other side in the O axis direction is formed.

The motor 3 is accommodated inside the casing 5 with a space in the O axis direction between itself and the compressor 2. The motor 3 includes a rotor 31 and a stator 32. The rotor 31 is fixed to be integrated with the shaft 21. The stator 32 is disposed on an outer circumference side of the rotor 31.

The rotor 31 is integrated with the shaft 21 and rotatable about the O axis. The rotor 31 is directly connected to an outer circumference side of the shaft 21, which is the outside in a circumferential direction with respect to the O axis so that it integrally rotates with the shaft 21 of the compressor 2 without intervening of gears and the like. The rotor 31 includes, for example, a rotor core (not shown) in which an induced current flows when the stator 32 generates a rotating magnetic field.

A gap 33 in the circumferential direction is provided between the stator 32 and the rotor 31 which covers the rotor 31 from the outer circumference side. The stator 32 includes a plurality of stator cores (not shown) that are disposed in, for example, the circumferential direction of the rotor 31, and a stator winding (not shown) wound on the stator core. When a current flows from the outside, the stator 32 generates a rotating magnetic field and rotates the rotor 31. The stator 32 is fixed into the casing 5.

The bearing 4 is accommodated inside the casing 5 and rotatably supports the shaft 21. The bearing 4 of this embodiment includes a plurality of journal bearings 41 and thrust bearings 42.

The journal bearing 41 supports a load on the shaft 21 in a radial direction with respect to the O axis. Journal bearings 41 are disposed at both ends of the shaft 21 in the O axis direction to sandwich the motor 3 and the compressor 2 in the O axis direction. The journal bearing 41 is also disposed between an area in which the compressor 2 is provided and an area in which the motor 3 is provided, which is on the motor 3 side relative to a sealing member 51 to be described below.

The thrust bearing 42 supports a load on the shaft 21 in the O axis direction through a thrust collar 21 a that is formed at the shaft 21. The thrust bearing 42 is disposed between the area in which the compressor 2 is provided and the area in which the motor 3 is provided and is on the compressor 2 side relative to the sealing member 51 to be described below.

The casing 5 accommodates the compressor 2 and the motor 3 therein. The casing 5 has a cylindrical shape along the O axis. An inner surface of the casing 5 protrudes toward the shaft 21 between the compressor 2 and the motor 3 in the O axis direction. The casing 5 is provided on a portion from which the sealing member 51 sealing a gap between the area in which the compressor 2 is provided and the area in which the motor 3 is provided protrudes.

In the heat exchange flow path 600, when a fluid is circulated therein, heat can be exchanged between the fluid flowing and the housing 23. Through the heat exchange flow path 600 of this embodiment, a fluid flows inside the stator 32 and the rotor 31 and the stator 32 are cooled. Through the heat exchange flow path 600, the fluid whose temperature has increased when the rotor 31 and the stator 32 are cooled flows inside the housing 23. Through the heat exchange flow path 600, the fluid that has flowed inside the housing 23 is supplied to and cooled by a heat exchanger 601 and flows again inside the stator 32. The heat exchange flow path 600 of this embodiment is a closed loop flow path through which the fluid is circulated between the motor 3 and the compressor 2.

Note that, as the fluid in this embodiment, for example, a cooling medium using a gas such as air and helium is preferably used. When a gas such as air and helium is used, compared to a gas including a large amount of liquid content such as a liquid and water vapor, it is possible to prevent a strength of a metal material forming the heat exchange flow path 600 from decreasing due to oxidation.

The heat exchange flow path 600 of the first embodiment includes the heat exchanger 601, an introduction flow path 602, a stator internal flow path 603, a first connecting flow path 604, a first housing flow path 605, and a first discharge flow path 606. The heat exchanger 601 cools the fluid that has flowed inside the housing 23. Through the introduction flow path 602, the fluid cooled by the heat exchanger 601 is introduced into the stator 32. The stator internal flow path 603 is connected to the introduction flow path 602 and circulates the fluid inside the stator 32. The first connecting flow path 604 is connected to the stator internal flow path 603, and supplies the fluid to the housing 23. The first housing flow path 605 is connected to the first connecting flow path 604 and circulates the fluid inside the housing 23. The first discharge flow path 606 is connected to the first housing flow path 605 and discharges the fluid from the inside of the housing 23 and supplies the fluid to the heat exchanger 601.

The heat exchanger 601 cools the fluid that has circulated inside the stator 32 and inside the housing 23. The heat exchanger 601 of this embodiment is disposed outside the casing 5. When the heat exchanger 601 exchanges heat between a surrounding secondary cooling medium and the fluid, the fluid is cooled to a temperature to which it is appropriate to cool the motor 3.

When the compressor system 10 is used for the subsea production system and is provided in the seabed, the surrounding seawater is preferably used as the secondary cooling medium. When the surrounding seawater is used, there is no need to provide an additional secondary cooling medium for the heat exchanger 601. That is, it is possible to cool the fluid to a temperature at which it is possible to sufficiently cool the motor 3 by simply exchanging heat with low temperature seawater in the seabed.

When the compressor system 10 is used for FPSO and is provided in a marine facility such as a ship, the surrounding air or fresh water stored in the marine facility is preferably used as the secondary cooling medium. When the surrounding air or fresh water is used, there is no need to provide an additional secondary cooling medium for the heat exchanger 601. In addition, it is possible to cool the fluid to a temperature to which it is possible to sufficiently cool the motor 3 while suppressing occurrences of events such as corrosion of a pipe.

Through the introduction flow path 602, the fluid is introduced into the stator 32 from the heat exchanger 601 on the upstream side in the O axis direction. The introduction flow path 602 is a pipe that is connected to the inside of the stator 32 from the heat exchanger 601 on an upstream side in the O axis direction of the stator 32. A pump 601 a configured to pressure-feed a fluid is provided along the introduction flow path 602.

The stator internal flow path 603 is disposed inside the stator 32, so that the fluid flows inside the stator 32. The stator internal flow path 603 of this embodiment is connected to the introduction flow path 602 and circulates the fluid from the upstream side to the downstream side in the O axis direction. The stator internal flow path 603 is a pipe that extends in the O axis direction at a portion close to the rotor 31 in the radial direction inside the stator 32. The stator internal flow path 603 extends inside the stator 32 from a position on the upstream side in the O axis direction relative to the rotor 31 to a position on the downstream side in the O axis direction relative to the rotor 31. An end of the stator internal flow path 603 on the upstream side in the O axis direction is connected to the introduction flow path 602.

Through the first connecting flow path 604, the fluid that has flowed in the stator internal flow path 603 and whose temperature has increased is circulated from the inside of the stator 32 to the outside of the casing 5 and is supplied to the inside of the housing 23. The first connecting flow path 604 of this embodiment is a pipe that extends to the outside of the casing 5 from the downstream side in the O axis direction of the stator 32 and is connected to the upstream side in the O axis direction of the housing 23. The first connecting flow path 604 is connected to an end of the stator internal flow path 603 on the downstream side in the O axis direction.

The first housing flow path 605 is disposed inside the housing 23, so that the fluid flows inside the housing 23. The first housing flow path 605 of this embodiment is connected to the first connecting flow path 604 and circulates the fluid from the upstream side to the downstream side in the O axis direction. The first housing flow path 605 is a pipe that extends in the O axis direction outward in the radial direction relative to the internal space 23 a in which the impeller 22 inside the housing 23 is disposed. An end of the first housing flow path 605 on the upstream side in the O axis direction is connected to the first connecting flow path 604.

Through the first discharge flow path 606, the fluid that has flowed in the first housing flow path 605 is discharged from the inside of the housing 23 to the outside of the casing 5 and is supplied to the heat exchanger 601. The first discharge flow path 606 is a pipe that is connected to the heat exchanger 601 from the inside of the housing 23 on the downstream side in the O axis direction of the housing 23. The first discharge flow path 606 is connected to an end of the first housing flow path 605 on the downstream side in the O axis direction.

When a temperature difference between the housing 23 and the impeller 22 satisfies a requirement of a predetermined reference, the flow rate adjusting unit 7 adjusts the flow rate of the fluid flowing in the heat exchange flow path 600. In the flow rate adjusting unit 7 of this embodiment, when the temperature difference between the housing 23 and the impeller 22 is less than a predetermined reference, the flow rate of the fluid flowing in the first connecting flow path 604 is reduced. In the flow rate adjusting unit 7, the temperatures of the housing 23 and the impeller 22 are not directly measured, the temperature of the fluid that has flowed in the first discharge flow path 606 is measured, and the temperature difference between the housing 23 and the impeller 22 is determined.

The flow rate adjusting unit 7 of this embodiment includes a temperature measuring unit 71, a valve 72, and a control unit 73. The temperature measuring unit 71 measures the temperature of the fluid flowing in the first discharge flow path 606. The valve 72 is provided in the first connecting flow path 604. The control unit 73 sends a signal to the valve 72 to adjust the degree of opening based on the measurement result of the temperature measuring unit 71.

The temperature measuring unit 71 is provided in the first discharge flow path 606. The temperature measuring unit 71 is a thermometer configured to measure the temperature of a fluid flowing in the first discharge flow path 606. The temperature measuring unit 71 sends the measured fluid temperature information to the control unit 73 as the measurement result.

The valve 72 switches a flowing state of the fluid flowing in the first connecting flow path 604. The valve 72 of this embodiment is a solenoid valve that is closed to restrict the first connecting flow path 604 when a signal from the control unit 73 is received.

When the measurement result of the temperature measuring unit 71 satisfies a requirement of a predetermined reference, the control unit 73 sends a signal to close the valve 72.

The predetermined reference in this embodiment is, for example, a temperature difference at which it can be regarded that there is no possibility of the housing 23 and the impeller 22 coming in contact. Specifically, the temperature difference at which it can be regarded that there is no possibility of the housing 23 and the impeller 22 coming into contact with each other is a temperature difference between the housing 23 and the impeller 22 when the housing 23 and the impeller 22 are sufficiently heated, such as, for example, when an operation is performed normally.

The control unit 73 of this embodiment includes an input unit 731, a determination unit 732, and an output unit 733. The measurement result is input to the input unit 731 from the temperature measuring unit 71. The determination unit 732 determines whether the obtained measurement result satisfies a requirement of a predetermined reference based on the result input to the input unit 731. The output unit 733 sends a signal to the valve 72 according to the determination result of the determination unit 732.

According to the compressor system 10 described above, a current is supplied to the stator 32 by an external device such as a generator (not shown). A rotating magnetic field is generated based on the supplied current and the rotor 31 of the motor 3 starts rotating together with the shaft 21. When the shaft 21 rotates at a high speed, in the compressor 2, the impeller 22 that rotates together with the shaft 21 compresses a working fluid flowing into the compressor 2 from the upstream side in the O axis direction and discharges the compressed fluid from the downstream side in the O axis direction.

In the motor 3, the fluid cooled by the heat exchanger 601 is introduced into the stator 32 through the introduction flow path 602 and flows in the stator internal flow path 603. Therefore, a portion close to the rotor 31 of the stator 32 is cooled. Therefore, the rotor 31 and the stator 32 heated due to heat generated between the rotor 31 and the stator 32 can be cooled.

The fluid whose temperature has increased when the rotor 31 and the stator 32 are cooled is discharged once to the outside of the casing 5 from the stator internal flow path 603 through the first connecting flow path 604. Then, the fluid whose temperature has increased is supplied to the first housing flow path 605. When the fluid whose temperature has increased flows in the first housing flow path 605, heat is exchanged between the fluid and the housing 23. As a result, the housing 23 is heated. That is, heat exhausted generated by cooling the rotor 31 and the stator 32 is used so as to efficiently and quickly heat the housing 23. As a result, according to a temperature change in the impeller 22 when the compressor system 10 is activated or stopped, it is possible to quickly heat the housing 23. Therefore, it is possible to reduce a difference between the amount of thermal elongation of the impeller 22 and the amount of thermal elongation of the housing 23. Therefore, it is possible to prevent a space between the impeller and the housing from being excessively narrowed while the compressor system is activated or stopped.

The fluid that has flowed in the first housing flow path 605 is supplied to and cooled by the heat exchanger 601 through the first discharge flow path 606. Then, the fluid is supplied again to the stator internal flow path 603 from the introduction flow path 602. Because the heat exchange flow path 600 is formed as a closed loop flow path in this manner, there is no need to supply new fluid. Therefore, it is possible to decrease the flow rate of the fluid flowing in the heat exchange flow path 600.

The fluid is cooled by the heat exchanger 601 so as to efficiently cool the fluid to a temperature to which it is possible to sufficiently cool the rotor 31 and the stator 32. That is, a fluid whose temperature has increased too much to cool the rotor 31 and the stator 32 by flowing in the stator internal flow path 603 and the first housing flow path 605 and thus can be cooled by exchange of heat with the secondary cooling medium through the heat exchanger 601. Therefore, it is possible to efficiently reduce the temperature of the fluid.

The fluid that is sufficiently cooled by the heat exchanger 601 flows in the stator internal flow path 603. Therefore, a fluid that can cool the rotor 31 and the stator 32 in the O axis direction with high accuracy can flow inside the stator 32. Therefore, when the rotor 31 rotates, the rotor 31 and the stator 32 that are heated due to heat generated between the rotor 31 and the stator 32 can be efficiently cooled over the O axis direction. Therefore, it is possible to suppress the occurrence of a locally high temperature area in the rotor 31 and the stator 32. As a result, it is possible to suppress a decrease in efficiency of the motor 3 and increase the lifespan thereof.

The temperature measuring unit 71 measures the temperature of the fluid flowing in the first discharge flow path 606 and sends the measurement result to the input unit 731 of the control unit 73. In the control unit 73, the measurement result input from the input unit 731 is sent to the determination unit 732. The determination unit 732 determines whether the measured temperature satisfies a requirement of a predetermined reference. Therefore, the determination unit 732 determines whether a temperature difference between the housing 23 and the impeller 22 has a value at which it can be regarded that there is no risk of the housing 23 and the impeller 22 coming in contact. When the determination unit 732 determines that a requirement of a reference is satisfied, a signal is sent from the output unit 733 to the valve 72. Therefore, the valve 72 is closed to restrict a flow rate of the fluid flowing in the first connecting flow path 604.

Therefore, the determination unit 732 can determine whether the housing 23 and the impeller 22 are sufficiently heated and a temperature difference is reduced, likewise, when an operation is performed normally. That is, it is possible to determine whether the housing 23 is sufficiently heated and a difference between an amount of thermal elongation of the impeller 22 and the amount of thermal elongation of the housing 23 is reduced.

When the determination unit 732 determines that a requirement of a reference is satisfied, the control unit 73 causes the valve 72 to be closed. Therefore, it is possible to circulate only a necessary amount of the fluid in the heat exchange flow path 600. Therefore, for example, when the temperature difference between the housing 23 and the impeller 22 is sufficiently small and there is no need to heat the housing 23, it is possible to prevent the fluid from being continuously circulated in the heat exchange flow path 600. Therefore, it is possible to efficiently circulate the fluid in the heat exchange flow path 600.

Second Embodiment

Next, a compressor system 12 according to a second embodiment will be described with reference to FIG. 2.

In the second embodiment, the same components as in the first embodiment are denoted with the same reference numerals and details thereof will not be described. In the compressor system 12 of the second embodiment, the configuration of a heat exchange flow path 620 is different from that of the first embodiment.

In the heat exchange flow path 620 of the compressor system 12 of the second embodiment, a compressed fluid that is a working fluid compressed by the impeller 22 is used as a fluid, and the fluid is circulated in the gap 33 (hereinafter simply referred to as the “gap 33”) between the stator 32 and the rotor 31. Specifically, as shown in FIG. 2, the heat exchange flow path 620 of the second embodiment includes a middle stage extracted fluid introduction flow path 622, a second connecting flow path 624, a second housing flow path 625, and a second discharge flow path 626. Through the middle stage extracted fluid introduction flow path 622, the compressed fluid is extracted from a middle stage of the compressor 2 and is introduced into the gap 33 of the motor 3.

Through the second connecting flow path 624, the compressed fluid that has flowed in the gap 33 is supplied to the housing 23. The second housing flow path 625 is connected to the second connecting flow path 624and the compressed fluid flows inside the housing 23. The second discharge flow path 626 is connected to the second housing flow path 625 and the compressed fluid is discharged to the outside of the casing 5 from the inside of the housing 23.

Note that the gap 33 in this embodiment is a space that is formed between the stator 32 and the rotor 31. The gap 33 is a space interposed between surfaces that face each other in the radial direction, between an outer circumference surface facing outward in the radial direction of the rotor 31 and an inner circumference surface facing inward in the radial direction of the stator 32.

Through the middle stage extracted fluid introduction flow path 622, the compressed fluid compressed by the impeller 22 is extracted from the middle stage of the compressor 2 and is supplied to the upstream side in the O axis direction of the gap 33. The middle stage extracted fluid introduction flow path 622 of this embodiment is a pipe that is connected from the middle stage of the compressor 2 to the upstream side in the O axis direction of the motor 3 inside the casing 5. The middle stage extracted fluid introduction flow path 622 is connected to the upstream side in the O axis direction relative to the rotor 31 and the stator 32 inside the casing 5. That is, through the middle stage extracted fluid introduction flow path 622, the compressed fluid is supplied to the gap 33 from the upstream side in the O axis direction. In the middle stage extracted fluid introduction flow path 622, the valve 72 is provided at a portion that is positioned outside the casing 5.

Through the second connecting flow path 624, the compressed fluid that has flowed in the gap 33 from the upstream side to the downstream side in the O axis direction is extracted from the gap 33 and is supplied to the second housing flow path 625. The second connecting flow path 624 is a pipe that is connected from the housing 23 to the downstream side in the O axis direction of the motor 3 inside the casing 5. The second connecting flow path 624 is connected to the downstream side in the O axis direction relative to the rotor 31 and the stator 32 inside the casing 5. That is, through the second connecting flow path 624, the compressed fluid is extracted from the gap 33 on the downstream side in the O axis direction.

The second housing flow path 625 is disposed inside the housing 23, so that the fluid flows inside the housing 23. The second housing flow path 625 is connected to the second connecting flow path 624, so that the compressed fluid flows to the downstream side from the upstream side in the O axis direction through the second housing flow path. The second housing flow path 625 is a pipe that extends in the O axis direction outward in the radial direction relative to the internal space 23 a in which the impeller 22 inside the housing 23 is disposed. An end of the second housing flow path 625 on the upstream side in the O axis direction is connected to the second connecting flow path 624.

The second discharge flow path 626 is connected to the second housing flow path 625 so that the compressed fluid flowing inside the housing 23 is discharged from the downstream side in the O axis direction to the outside of the casing 5. The second discharge flow path 626 is a pipe that is connected to the outside of the casing 5 from the inside of the housing 23 on the downstream side in the O axis direction of the housing 23. The second discharge flow path 626 is connected to an end of the second housing flow path 625 on the downstream side in the O axis direction. In the second discharge flow path 626, the temperature measuring unit 71 is provided at a portion that is positioned outside the casing 5.

According to the compressor system 12 described above, the compressed fluid that is a working fluid compressed by the impeller 22 is extracted from the middle stage of the compressor 2 through the middle stage extracted fluid introduction flow path 622. Then, the compressed fluid is supplied to the upstream side in the O axis direction of the gap 33. Therefore, the compressed fluid flows in the gap 33 from the upstream side to the downstream side in the O axis direction and the vicinity of the gap 33 is cooled in the O axis direction. Therefore, the rotor 31 and the stator 32 heated due to heat generated when the rotor 31 rotates can be cooled.

The compressed fluid that has flowed in the gap 33 is extracted from the downstream side in the O axis direction of the gap 33 through the second connecting flow path 624 and is supplied to the second housing flow path 625. Therefore, it is possible to heat the housing 23 due to the compressed fluid whose temperature has increased when the rotor 31 and the stator 32 are cooled. That is, heat exhausted generated by cooling the rotor 31 and the stator 32 is used so as to efficiently and quickly heat the housing 23. As a result, according to a temperature change in the impeller 22 when the compressor system 10 is activated or stopped, it is possible to quickly heat the housing 23. Therefore, it is possible to reduce a difference between the amount of thermal elongation of the impeller 22 and the amount of thermal elongation of the housing 23. Therefore, it is possible to prevent a space between the impeller and the housing from being excessively narrowed while the compressor system is activated or stopped.

A part of the working fluid compressed by the compressor 2 is extracted and is used as the fluid flowing in the heat exchange flow path 620. Therefore, the fluid can flow in the heat exchange flow path 620 without using a device configured to send a fluid such as the pump 601 a. The rotor 31 and the stator 32 are cooled by the working fluid whose temperature has increased when it is compressed by the impeller 22. Therefore, the working fluid can be further heated and supplied to the housing 23. Therefore, it is possible to effectively heat the housing 23 with a simple configuration.

Third Embodiment

Next, a compressor system 13 of a third embodiment will be described with reference to FIG. 3.

In the third embodiment, the same components as in the first embodiment and the second embodiment are denoted with the same reference numerals and details thereof will not be described. In the compressor system 13 of the third embodiment, a configuration of a heat exchange flow path 630 is different from those of the first embodiment and the second embodiment.

In the heat exchange flow path 630 of the compressor system 13 of the third embodiment, unlike the second embodiment, a compressed fluid is used as a fluid and the fluid is not supplied to the motor 3 side. Specifically, as shown in FIG. 3, the heat exchange flow path 630 of the third embodiment includes a second middle stage extracted fluid introduction flow path 632. Through the second middle stage extracted fluid introduction flow path 632, the compressed fluid that has been compressed is extracted from the middle stage of the compressor 2 and is supplied to the second housing flow path 625. Similarly to the second embodiment, the heat exchange flow path 630 of the third embodiment includes the second housing flow path 625 and the second discharge flow path 626.

Through the second middle stage extracted fluid introduction flow path 632, the compressed fluid compressed by the impeller 22 is extracted from the middle stage of the compressor 2 and is supplied to the second housing flow path 625. The second middle stage extracted fluid introduction flow path 632 of this embodiment is a pipe that is connected from the middle stage of the compressor 2 to the upstream side in the O axis direction of the second housing flow path 625. In the second middle stage extracted fluid introduction flow path 632, the valve 72 is provided at a portion that is positioned outside the casing 5.

According to the compressor system 13 described above, a part of the working fluid compressed by the compressor 2 is extracted and used as the fluid flowing in the heat exchange flow path 620. Therefore, the fluid can flow in the heat exchange flow path 620 without using a device configured to send a fluid such as the pump 601 a. The working fluid whose temperature has increased when it is compressed by the impeller 22 can be supplied to the housing 23. Therefore, it is possible to effectively heat the housing 23 with a simple configuration.

Fourth Embodiment

Next, a compressor system 14 according to a fourth embodiment will be described with reference to FIG. 4.

In the fourth embodiment, the same components as in the first embodiment to The third embodiment are denoted with the same reference numerals and details thereof will not be described. In the compressor system 14 of the fourth embodiment, the configuration of a heat exchange flow path 640 is different from those of the first embodiment to the third embodiment.

When the compressed fluid is used as the fluid flowing in the heat exchange flow path 640, the present invention is not limited to the compressed fluid that is extracted from the middle stage of the compressor 2 as in the second embodiment and the third embodiment, and the working fluid compressed by the impeller 22 can be extracted. Therefore, for example, the compressed fluid may be extracted from the last stage of the compressor 2.

In the heat exchange flow path 640 of the compressor system 14 of the fourth embodiment, the compressed fluid is extracted from the last stage of the compressor 2. Specifically, as shown in FIG. 4, the heat exchange flow path 640 of the fourth embodiment includes a later stage extracted fluid introduction flow path 642 through which the compressed fluid is extracted from the last stage of the compressor 2 and is supplied to the second housing flow path 625.

Through the later stage extracted fluid introduction flow path 642, the compressed fluid while it is maximally compressed by the impeller 22 is extracted from the last stage of the compressor 2 and is supplied to the second housing flow path 625. The later stage extracted fluid introduction flow path 642 of this embodiment is a pipe that is connected from the last stage of the compressor 2 to the upstream side in the O axis direction of the second housing flow path 625. The later stage extracted fluid introduction flow path 642, through which the compressed fluid is discharged to the outside of the housing 23, is connected to a discharge port (not shown) that is provided in the last stage of the compressor 2. In the later stage extracted fluid introduction flow path 642, the valve 72 is provided at a portion that is positioned outside the casing 5.

According to the compressor system 14 described above, the housing 23 can be heated by the compressed fluid having a higher temperature than that of the third embodiment.

The embodiments of the present invention have been described in detail above with reference to the drawings, but configurations and combinations thereof in the embodiments are only examples, and additions, omissions, substitutions and other modifications of the configurations can be made without departing from the scope of the present invention. In addition, the present invention is not limited to the embodiments and is only limited by the scope of the appended claims.

Note that the present invention is not limited to the heat exchanger 601 that is disposed outside the casing 5 as in the first embodiment and a heat exchanger that can cool a fluid may be provided at any position. For example, the heat exchanger 601 may be disposed inside the casing 5. The number of heat exchangers 601 is not limited to one as in this embodiment, but a plurality of heat exchangers 601 may be provided.

A method of determining a temperature difference between the housing 23 and the impeller is not limited to the method in which the temperatures of the fluids that have circulated in the first housing flow path 605 and the second housing flow path 625 are measured as in this embodiment. A temperature difference between the housing 23 and the impeller may be determined by directly measuring the temperatures of the housing 23 and the impeller 22. A temperature difference between the housing 23 and the impeller may be determined according to the rotational speed of the shaft 21 when a relationship between the temperature difference between the housing 23 and the impeller 22 and the rotational speed of the shaft 21 is determined in advance.

The first housing flow path 605 and the second housing flow path 625 through which the fluid is supplied to the housing 23 are not limited to paths having a structure that extends in the O axis direction inside the housing 23 as in this embodiment. The first housing flow path 605 and the second housing flow path 625 may have a configuration in which heat can be exchanged between the fluid that circulates therein and the housing 23. For example, the first housing flow path 605 and the second housing flow path 625 may be provided between the housing 23 and the casing 5. In this case, the first housing flow path 605 and the second housing flow path 625 may be spirally wound on an outer circumference of the housing 23 or may be disposed to extend in a linear shape in the O axis direction.

INDUSTRIAL APPLICABILITY

According to the above compressor system, it is possible to heat the housing using the fluid whose temperature has increased when the rotor and the stator are cooled. As a result, it is possible to prevent a space between the impeller and the housing from being excessively narrowed.

REFERENCE SIGNS LIST

10, 12, 13, 14 Compressor system

O Axis

2 Compressor

21 Shaft

21 a Thrust collar

22 Impeller

23 Housing

23 a Internal space

3 Motor

31 Rotor

32 Stator

33 Gap

4 Bearing

41 Journal bearing

42 Thrust bearing

5 Casing

51 Sealing member

600, 620, 630, 640 Heat exchange flow path

601 Heat exchanger

601 a Pump

602 Introduction flow path

603 Stator internal flow path

604 First connecting flow path

605 First housing flow path

606 First discharge flow path

7 Flow rate adjusting unit

71 Temperature measuring unit

72 Valve

73 Control unit

731 Input unit

732 Determination unit

733 Output unit

622 Middle stage extracted fluid introduction flow path

624 Second connecting flow path

625 Second housing flow path

626 Second discharge flow path

632 Second middle stage extracted fluid introduction flow path

642 Later stage extracted fluid introduction flow path Page 2 of 3 

1. A compressor system comprising: a motor including a rotor configured to rotate about an axis and a stator disposed on an outer circumference side of the rotor; a compressor including an impeller configured to compress a working fluid by rotating together with the rotor and a housing covering the impeller from an outer circumference side; and a heat exchange flow path through which a fluid flowing inside the stator or in a gap between the stator and the rotor is flowed and heat is exchangeable between the fluid and the housing. wherein the heat exchange flow path comprises a housing flow path disposed inside the housing so that the fluid flows inside the housing.
 2. The compressor system according to claim 1, wherein the fluid is a working fluid compressed by the impeller.
 3. The compressor system according to claim 1, comprising a flow rate adjusting unit configured to adjust a flow rate of the fluid flowing in the heat exchange flow path when a temperature difference between the housing and the impeller satisfies a requirement of a predetermined reference. 